Global Positioning System (GPS) satellites provide two time references to determine accurate time referenced to either GPS time or Universal Time Coordinated (UTC). GPS receivers process the received satellite signals to provide a precise 1 pulse-per-second (1 PPS) signal, referenced to either GPS time or UTC. Moreover, various communications equipment also require a precise 1 PPS signal, referenced to UTC for synchronization. However, when the GPS receiver is not in close proximity to the communications system to be synchronized, the use of long cables are necessary to connect the two. However, extending cables over long lengths causes the system operator to measure the cable length, as well as its corresponding delay time, and include this measurement into the overall system timing. This is typically a manual process and is prone to error of operator entry or mis-measurement of cable length. Further, it also adds to the overall installation time, thereby resulting in a higher installation cost.
Referring to U.S. Pat. No. 4,827,437 and U.S. Pat. No. 4,814,689, techniques for measuring cable delay time are disclosed. However, neither of these patents discuss or suggest the use of the PPS of a GPS receiver to accurately synchronize remote equipment.